Product manual

Installation
28 025-9158L
Pin/Signal Description
OUT-1&2 (GND) Connected to Model 26 chassis ground.
OUT-3 (RXD) This is an input and carries the data being received. It is also
connected to IN-4.
OUT-4 (TXD) This is an output and carries the data being transmitted. It is also
connected to IN-3.
OUT-5&6 (GND) Connected to Model 26 chassis ground.
IN-1&2 (GND) Connected to Model 26 chassis ground.
IN-3 (TXD) This is an output and carries the data being transmitted. It is also
connected to OUT-4.
IN-4 (RXD) This is an input and carries the data being received. It is also
connected to OUT-3.
IN-5&6 (GND) Connected to Model 26 chassis ground.
J14 Connector
This connector is the outside connector of the two on the left side of the rear panel. The
following are the pin descriptions for this connector:
Pin Description
1
(PTT)
This is the Push-to-Talk output for interfacing to radios. It is an open-drain
output. It is grounded when the Model 26 starts transmitting and remains
grounded until the transmission ends. At all other times it is in the open drain
state.
2
(GND)
This pin is connected to chassis ground.
3 to 8 Not Connected
9
(+AUD 2W RX/TX)
This pin is the positive side of the transformer coupled audio output and 2-wire
input. If used as a 2-wire system JP11 sets the input impedance. The output
levels are adjusted by potentiometers FFSK XMIT (R79), MIC XMIT (R30),
and TONE XMIT (R63). Input levels from this pin are adjusted by
potentiometer RCV 2W (R81).
10
(-AUD 2W RX/TX)
This pin is the negative side of the transformer coupled audio output and 2-wire
input. Refer to the description of pin 9 above.
11 and 12 Not Connected